Multi-section bridge supporting structure of steel or reinforced concrete having supports centrally of the cross-section of the structure

ABSTRACT

Bridge or highway supporting structure of steel concrete or prestressed concrete for multiple section structure with columns disposed centrally of the cross-section of the bridge, a superstructure of beams in the form of slabs rigidly connected to the columns with at least one slab-shaped longitudinal girder and slab-shaped transverse beams of the same structural height as the longitudinal girders where the columns are slender in the direction longitudinally of the bridge supporting structure and relatively wider transversely thereof and connected with the transverse beams with a pedestal at the foot of each column, a foundation block below each pedestal and bearings intermediate the pedestal and the foundation block which are spaced transversely of the structure to permit tilting movement of the bridge in longitudinal direction.

United States Patent Finsterwalder et al.

MULTI-SECTION BRIDGE SUPPORTING STRUCTURE OF STEEL OR REINFORCED CONCRETE HAVING SUPPORTS CENTRALLY OF THE CROSS-SECTION OF THE STRUCTURE Ulrich Finsterwalder, M unich- Obe rmenzing; Klemens Finsterwalder, Socking, both of Germany Dyckerholl 8r Wldmann Kommandltgeeellschaft, Munich, Germany Filed: June 12, 1970 Appl. No.: 45,839

inventors:

Assignee:

Foreign Application Priority Data June 11, 1969 Germany ..P 19 29 702.0

References Cited UNITED STATES PATENTS Schneider 14/1 2,161,176 6/1939 Leisner ..52/87 X 2,161,177 6/1939 Leisner ..52/87 X 2,477,256 7/1949 Kneas 52/73 X 3,416,175 12/1968 Hutchinson r 14/1 3,460,446 8/1969 Finsterwalder ..94/l R Primary Examiner-Jacob L. Nackenofi' Attorney-Robert H. Jacob 5 7] ABSTRACT Bridge or highway supporting structure of steel concrete or prestressed concrete for multiple section structure with columns disposed centrally of the cross-section of the bridge, a superstructure of beams in the form of slabs rigidly connected to the columns with at least one slab-shaped longitudinal girder and slab-shaped transverse beams of the same structural height as the longitudinal girders where the columns are slender in the direction longitudinally of the bridge supporting structure and relatively wider transversely thereof and connected with the transverse beams with a pedestal at the foot of each column, a foundation block below each pedestal and bearings intermediate the pedestal and the foundation block which are spaced transversely of the structure to permit tilting movement of the bridge in longitudinal direction.

5 Claims, 8 Drawing Figures P'ATENTEDIM 1a m:

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SHEET 2 OF 2 r J 3 1 13 13 -13 11:13 1:13 Jpn #1 C i U u U 3 Fig. 5 1s MULTI-SECTION BRIDGE SUPPORTING STRUCTURE OF STEEL OR REINFORCED CONCRETE HAVING SUPPORTS CEN'IRALLY OF THE CROSS-SECTION OF THE STRUCTURE BACKGROUND OF THE INVENTION girder.

The present invention relates to bridges and elevated highway structures and particularly the supporting parts thereof. More in particular, the invention relates to a multiseetion bridge supporting structure made of steel concrete or reinforced concrete having supports disposed centrally of the cross-section of the bridge which are connected with the upper bridge structure and which are connected in a manner to resist bending with the upper bridge structure that is con structed in the form of a plate girder.

Among supporting systems used in bridge construction those in which the upper structure is separated from the supports or columns are most extensively used. In this connection, the separation of the structural components that are subjected to bending from the columns or pylons subjected to pressure, and which originated with the beginning of structural engineering, was taken over.

Steel concrete construction, particularly prestressed concrete construction, however, is subject to its own laws or requirements which lead to different forms of construction if it is desired to economically exploit the available cross-sections and take into consideration the existing local conditions. Thus, a mushroom-shaped form of construction has proven itself as a bridge supporting structure which is keyed to the requirements of steel concrete and of prestressed concrete, where plate-shaped superstructures cantilever out on all sides from the support that is suitably disposed at the center of gravity U.S. Pat. No. 3,] l4,302). In order to make it possible to absorb the cantilever moments that increase with increasing overhang of the superstructure, it is not possible to avoid a considerable increase of the structural height at the start of the support. Furthermore, the support which is rigidly connected at the foundation has to be relatively thick in order to insure of the necessary stability.

In order to keep the height or thickness of such bridge structures lower for approximately the same width of spans, runway plate sections in the form of hung supports are arranged in a bridge-like highway structure between runway plate sections which cantilever out on all sides in a mushroom-like manner that have become known from U.S. Pat. No. 3,477,080. Inasmuch as the cantilever of the mushroom-like sections from the supports is smaller in this form of embodiment and the cantilever moment grows only linearly out of the transverse forces imparted at the bearing support of the suspension carriers, it is possible in this manner to obtain a decrease of the structural height for approximately the same width of span. With a span width of approximately 30 m, there results a structural height of 0.50 m in the section, and at the support connection a height of about 1.50 m.

The requirement for an increase of the width of the span has resulted in constructing this known supporting structure also with continuous longitudinal girders. It is possible in this manner to obtain spans up to approximately 40 m, but the structural height of the plate girder section is about 2 m to 3 m which is considered a disadvantage, especially with urban high-ways where it is necessary to maintain a clearance space and to have the ramp slopes for approaching runways short, this must be considered to be unfavorable.

SUMMARY OF THE INVENTION As a whole, bridge supporting structures whose superstructure rests upon a row of supports or columns arranged along the Iongtitudinal central axis and whose supports are built in with the superstructure have proven themselves. An essential advantage resides in the simpler construction made possible by the arrangement of the columns centrally of the cross-section of the bridge by means of movable scaffolding structures that span a section, because these can travel along with their sides laterally of the columns into the next section. In addition, such single column bridge supporting structures can frequently be fitted in better where the space conditions are limited.

It is an object of the invention to create a bridge superstructure which is of smaller structural height and uses thinner supports or columns which can be well adapted to different widths and is advantageous as to production or construction.

In accordance with the invention, a multiple section bridgesupporting structure of steel concrete or prestressed concrete of the aforementioned type is realized by the combination of the following features known per se and in partial combination:

a. the bridge supporting structure has one or more slabshaped longitudinal supports or girders,

b. slab-shaped transverse beams of the same structural height or thickness as the longitudinal girders,

c. slender columns or supports in the longitudinal direction of the bridge and broad ones transversely thereof which are connected with the transverse beams, and

d. its columns are supported at the foot of the column on supports arranged at the distance from one another transversely of the bridge which makes possible a tilting motion in the longitudinal direction of the bridge.

It is a main feature of the bridge supporting structure in accordance with the invention that the columns are slender or narrow in the longitudinal direction of the bridge and rest at the bottom on supports which permit tilting moments. In this manner, the forces acting longitudinally of the bridge that result from changes in temperature and from brake loads of the traffic are evenly distributed onto all columns. Moments at the point of fixation arise merely at the head of the column, while they become zero at the bottom of the column. Owing to the slender construction of the columns, the moments are maintained small in relation to their absolute magnitude. Transversely of the bridge a similar condition is obtained owing to the spreading of the tilting supports at the bottom of the column which is similar to an encasement if the spreading is selected to be so large that the eccentricity of the resultant of dead weight and trafiic loads remains within the core of the cross-section of the column.

To this are added the advantages of low production costs that result from the shape of the superstructure because the slab-shaped longitudinal girders require a small expenditure for forms and the placing of their armoring is simple. In addition, it is advantageous that the superstructure is of uniform structural height over the entire length of the bridge supporting structure. In addition, this height is small; it amounts to not more than l.l0 m with support spacing or spans of about 35 m.

It is particularly advantageous if a part of the columns is supported on stationary tilting bearings or supports or another part of the columns on tilting roller bearings. The columns can be embedded at the top or head into a thickened mushroomlike part at the bottom side of the transverse beam and merge at the bottom with a pedestal type enlarged portion. The support width suitably is about one-eighth of the width of the bridge and the distance of the hearings or supports about onefourth of the width of the bridge.

A preferred embodiment of the bridge supporting structure has two longitudinal girders provided approximately at the quarter points of the bridge width.

DESCRIPTION OF THE DRAWINGS An embodiment of the invention is illustrated in the accompanying drawings in which FIG. 1 is a cross-section through the bridge supporting structure in the plane I--] of FIG. 2,

FIG. 2 is a bottom view and a section taken in the plane I]- II of FIG. 1,

FIG. 3-5 are schematic illustrations of embodiments with different static systems each in a side view, and

FIGS. 3a, 4a and a are bottom views of FIGS. 3, 4 and 5, respectively.

DESCRIPTION OF THE INVENTION In the bridge supporting structure shown in section in FIG. I, the superstructure has two slab-like longitudinal girders 2 which are connected by the slab 3 positioned at the top. A cantilever 4 extends on each side from the longitudinal girders which carries concrete parts consisting of ledge 5 and the guardstone 6. Transverse beams 7 are disposed about the single struts or props 8 which are provided along the longitudinal center axis. The longitudinal girders 2 are of the same structural height than the transverse beams 7.

The supports or columns 8 are rigidly held at their heads in flat mushroom-like expanding parts 9 below transverse beam 7 and widen at the bottom to merge with a broad pedestal 10 in order to achieve sufficient spreading of the bearings 11. The bearings are in the form of stationary tilting bearings or tilting roller bearings. They rest upon a foundation block 12.

The bridge supporting structure can be carried out in accordance with different static systems. Some examples are indicated in FIGS. 3-5.

Thus, in FIG. 3 a number of supporting structure components comprising columns 13 and superstructure sections 14 are mounted in a row which in each section or field are connected by a hinged sections 15. The relevant bottom view is shown below the side view. All of the columns are supported on stationary tilting bearings; changes in length can be compensated for by the hinged sections 15.

An equally advantageous and statically defined or determined supporting system is shown in FIG. 4. Here suspension supports or slabs are disposed in each second section or span which are likewise connected with the superstructure parts 17 by hinged sections 15. The supports 13 again are resting exclusively on fixed tilting bearings because the changes in length can be absorbed in the hinged sections I5.

If gaps in the superstructure are completely waived, than it is necessary to place the columns 13 which are encased in the superstructure 18 at the lower end at least partly upon tilting roller bearings, and in particular only the two central columns rest on tilting bearings, the outer columns on tilting roller bearings in order to make possible longitudinal compensation. The patent claim 1 which follows covers only the total combination of the features recited therein.

Having now described the invention with reference to the accompanying drawings what we desire to protect by letters patent of the United States is set forth in the appended claims.

We claim:

1. Multiple section supporting structure for bridges and highways of reinforced or prestressed concrete comprising columns disposed centrally of the cross section of the structure, each section comprising a superstructure in the form of slab girders rigidly connected to said columns including a pair of slab shaped longitudinal girders and transverse slabs defining transverse beams, said transverse beams having substantially the same structural height as said longitudinal girders, said columns being relatively slender in the direction longitudinally of the structure and having relatively wider sides transversely thereof and being rigidly connected along said relatively wider sides with said transverse beams, a pedestal at the foot of each column, a foundation block below each pedestal and bearing elements intermediate each pedestal and foundation block, said bearing elements being spaced transversely of the structure and permitting tilting movement in a direction longitudinally of the structure.

2. Bridge supporting structure in accordance with claim I where some of said columns are supported on stationary tilting bearings and others are supported on tilting roller bearings.

3. Bridge supporting structure in accordance with claim I where said columns widen at the top to form a mushroom-like expansion on said transverse beam with which they are connected and expand at the bottom toward said pedestal.

. Bridge supporting structure in accordance with claim I,

where the width of the columns is approximately one-eighth of the width of the bridge and the spacing of the bearings is approximately one-fourth of the width of the bridge.

5. Bridge supporting structure in accordance with claim 1 comprising a pair of longitudinal girders disposed at the quarter points of the width of said bridge. 

1. Multiple section supporting structure for bridges and highways of reinforced or prestressed concrete comprising columns disposed centrally of the cross section of the structure, each section comprising a superstructure in the form of slab girders rigidly connected to said columns including a pair of slab shaped longitudinal girders and transverse slabs defining transverse beams, said transverse beams having substantially the same structural height as said longitudinal girders, said columns being relatively slender in the direction longitudinally of the structure and having relatively wider sides transversely thereof and being rigidly connected along said relatively wider sides with said transverse beams, a pedestal at the foot of each column, a foundation block below each pedestal and bearing elements intermediate each pedestal and foundation block, said bearing elements being spaced transversely of the structure and permitting tilting movement in a direction longitudinally of the structure.
 2. Bridge supporting structure in accordance with claim 1 where some of said columns are supported on stationary tilting bearings and others are supported on tilting roller bearings.
 3. Bridge supporting structure in accordance with claim 1 where said columns widen at the top to form a mushroom-like expansion on said transverse beam with which they are connected and expand at the bottom toward said pedestal.
 4. Bridge supporting structure in accordance with claim 1, where the width of the columns is approximately one-eighth of the width of the bridge and the spacing of the bearings is approximately one-fourth of the width of the bridge.
 5. Bridge supporting structure in accordance with claim 1 comprising a pair of longitudinal girders disposed at the quarter points of the width of said bridge. 